Ecasound Infinite Silent Input Source Syntax

This article explains how to define an infinite silent input stream in Ecasound, covering the exact command-line syntax required, how Ecasound processes null audio, and practical examples for generating silence for testing or audio production.

In Ecasound, the syntax to specify an infinite silent audio input is null, defined using the input flag -i:

-i null

Alternatively, the colon format can be used interchangeably:

-i:null

When null is declared as an input source, Ecasound continuously generates sample frames containing only zeros. This stream runs indefinitely until the process is manually stopped or limited by a processing duration parameter.

Controlling Audio Properties

The silent stream inherits the audio format of the current chainsetup. You can customize the sample rate, channel count, and bit depth using the -f option:

ecasound -f:s16_le,2,44100 -i null -o alsa

In this command:

• -f:s16_le,2,44100 formats the stream to 16-bit little-endian, stereo (2 channels), at 44,100 Hz.
• -i null supplies continuous silence matching those specifications.
• -o alsa routes the silent stream to your system's ALSA sound output.

Creating Fixed-Length Silent Files

Because -i null creates an infinite stream, you must use the -t (time) option if you want to render a specific duration of silence to a file:

ecasound -f:s16_le,2,48000 -i null -t:10 -o silence_10sec.wav

This generates a 10-second WAV file containing pure digital silence at a 48 kHz sample rate.